The moving characteristics of frontal lines on the Yunnan-Guizhou Plateau

KeyWord:Frontal line on the Yunnan-Guizhou Plateau;Spatial-temporal features;Moving characteristics;Long-duration frontal line

Abstract:

      A method to approximate the surface frontal line on the Yunnan-Guizhou Plateau by linear fitting is proposed. Through comprehensive analysis of the frontal line position, the spatial distribution and temporal variation of meteorological elements around the frontal line, as well as changes in the position and direction of the frontal line for long-lasting frontal line events, the movement characteristics of the frontal line on the Yunnan-Guizhou Plateau are systematically revealed. The cold (warm) frontal lines are concentrated in 102.5°—105°E (104.5°—105.75°E) and the maximum cooling (heating) zone is located on the eastern (western) side of the frontal line. The changes in meteorological elements around the frontal line are closely related to the movement of the frontal line. The westward moving frontal line usually brings cooling condition, increases surface air pressure, and reduces sunshine hours around the frontal line, while the eastward-moving frontal line often leads to opposite changes. According to the movement of long-lasting frontal line events, frontal line events can be divided into three types: Stationary, westward and eastward. The stationary frontal lines are the most in all the three types. The westward moving frontal line can advance continuously and quickly and is accompanied by a clockwise swing of the frontal line. The eastward moving frontal line has a lower frequency and a relatively low speed. Overall, with the objective and quantitative description of the frontal line, especially its dynamic characteristics, the above results can provide an important reference for the fine forecast of various meteorological elements on the Yunnan-Guizhou Plateau.